The Reasons and Solutions for the Yellowing of Bulb Begonia Leaves
Bulb begonias are favored by horticulture enthusiasts for their vibrant flowers, but the issue of yellowing leaves often troubles growers. This article will delve into the three main causes of yellowing leaves and provide practical solutions to help restore the vitality of the plant.
One, Soil Environment Improvement
1.1 Hazards of Soil Hardening
Roots in compacted soil are like being wrapped in plaster, unable to breathe and absorb nutrients properly. When the soil pH value is greater than 7.5, the absorption of iron is hindered, with typical symptoms being the interveinal yellowing of new leaves. It is recommended to test the soil pH with pH paper every quarter.
1.2 Guidelines for Soil Replacement
Use a mixture of decomposed leaf soil, perlite, and vermiculite in a ratio of 5:3:2. For disinfection, a microwave oven can be used for 3 minutes at high temperature instead of chemical agents. After potting, it is necessary to acclimate for 7 days in a diffused light environment, and apply a light fertilizer after new roots have sprouted.
Two, Optimization of Light Management
2.1 Light Intensity Test
During 10:00-15:00 in the summer, 60% shading is required, and a lux meter can be used to ensure that the light intensity is between 10,000-15,000 lux. An eastern-facing balcony is ideal, and a shading curtain needs to be installed for west-facing windows. Full sun exposure is acceptable in winter.
2.2 Application of Supplemental Lighting Systems
During consecutive rainy days, supplemental LED grow lights can be used, with 4 hours of additional lighting per day and a distance of 40 cm from the plant. A smart timer plug can be set for a 14-hour/day light cycle to simulate a natural light environment.
Three, Precise Water Control
3.1 Watering Frequency Formula
In spring and autumn, use the 'finger test': insert the index finger into the soil up to two knuckles, and if it's dry, water. Test twice a day in summer and switch to midday testing in winter. Terra cotta pots require a 30% increase in watering frequency compared to plastic pots.
3.2 Upgrading the Drainage System
Place a 3cm thick layer of ceramic stones at the bottom of the pot and mix in 5% coarse river sand to improve permeability. If root rot occurs, soak the roots in 3% hydrogen peroxide for 15 minutes to effectively kill anaerobic bacteria. During the recovery period, use the immersion pot method to supply water and maintain 60% air humidity.
Through systematic environmental control, the yellowing of bulb begonia leaves can usually be improved within 2-3 weeks. It is recommended to establish a maintenance log to record data such as temperature, humidity, and fertilizing and watering, which can help identify issues in a timely manner. Regularly applying chelated iron fertilizer can prevent the recurrence of iron deficiency yellowing.